even though crypto and bitcoin is emerging and may grow bigger on the future banks will still remain the same as a gateway of transactions, keeper of savings and storage of important instrument because before crypto emerge bank is still the one who connects the two for you to buy bitcoin you need to have fiat who is deemed a legal tender.
They will only remain we keep fiat money, and why would we? Fiat money is worthless and enforced on us by our oppressive governments. If we switch to a better system based on cryptocurrencies we'll be able to skip fiat.
Think of it this way. You're getting paid in a cryptocurrency and are able to buy everything you need with it. You pay bills and taxes with it. Why would you suddenly want to buy fiat money? So that you can put it in a bank for 5% a year?